You could always try testing again. What about since your last period? Did you have unprotected sex? If so, it could be that you are pregnant from this past cycle. It seems like you would be overdue for your May period by now?

Early pregnancy symptoms can mimic PMS, so it's best to test again if you're unsure. If you're worried you're pregnant and a home test is not picking it up, see the doc and get a blood test done. That will tell you one way or another.

I am pregnant, and sometimes my discharge is yellowish and sometimes not, but I also had yellowish discharge on cycles where I was not pregnant.